/*
 * Copyright (c) 2013, EGE University, Izmir, Turkey
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the
 *   distribution.
 * - Neither the name of the copyright holders nor the names of
 *   its contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * @author: K. Sinan YILDIRIM (sinanyil81@gmail.com)
 */

module LogicalClockC
{
    provides
    {
        interface LogicalClock;
    }
}
implementation
{
    uint32_t offset;                    // offset of the logical clock
    float multiplier;                   // rate multiplier of the logical clock
    uint32_t lastUpdate;                // local time at which the offset of the logical clock is updated

    command void LogicalClock.start(){
        atomic{
            offset = 0;
            lastUpdate = 0;
            multiplier = 0.0;
        }
    }

    command void LogicalClock.setRate(float rate){
        atomic multiplier = rate;
    }

    async command float LogicalClock.getRate(){
        return multiplier;
    }

    command void LogicalClock.setValue(uint32_t value,uint32_t localTime){
        atomic{
            offset = value;
            lastUpdate = localTime;
        }
    }

    async command void LogicalClock.getValue(uint32_t *time){
        uint32_t timePassed = *time - lastUpdate;

        *time = offset;
        *time += timePassed + (int32_t)(multiplier*(int32_t)(timePassed));
        
    }
}